Synthesis of 1-(4-isopropenylphenoxy)-bromo-C2-C4-alkanes and application of their transformation products

Reaction of 4-isopropenylphenol with α,ω-dibromo-C₂-C₄-alkanes by the Willamson reaction in the presence of potassium iodide as promoter, aiming to synthesize the corresponding monobromosubstituted derivatives and to study their some chemical transformation. Optimal conditions to obtain 1-(4-isopropenylphenoxy)-2-bromoethane, 1-(4-isopropenylphenoxy)-3-bromopropane and 1-(4-isopropenylphenoxy)-4-bromobutane were found. The nitrogen-containing derivatives, inhibitors of a hydrosulfuric corrosion in the water-salt solutions, were obtained on the basis of the first two compounds. The derivatives involving multiple bond and ester-group were synthesized from the third compound. Their incorporation into the polystyrene chains in the process synthesis gives them plasticize properties.     

Stabilization of systems with distributed and lumped parameters

Kamsk Polytechnic Institute, Naberezhnye Chelny. Translated from Prikladnaya Mekhanika, Vol. 27, No. 3, pp. 102–208, March, 1991.     

Observation of raman scattering by localized optical phonons bound to neutral donors in GaP:Si

Raman scattering by localized optical phonons bound to neutral donors with degenerate ground state has been observed in GaP:Si. The scattering efficiency was measured at T=6.0±0.1 K as a function of the net donor concentration N_D-N_A ranging from 1.6 ·10¹⁷ to 7.1· 10¹⁷ cm^-3. It is found that reasonable agreement with the theory of weakly coupled electron-phonon modes obtained if a Bohr radius of $\text{a}{}_0\text{=5.4}\text{A}\text{?}$ is used, whereas $\text{a}{}_0\text{=7.5}\text{A}\text{?}$ is obtained in the hydrogenic effective-mass approximation using the ionization energy E_D=86.7 meV.     

Discrete spectrum and principal functions of non-selfadjoint differential operator

In this article, we consider the operator L defined by the differential expression in L ₂(–, ), where q is a complex valued function. Discussing the spectrum, we prove that L has a finite number of eigenvalues and spectral singularities, if the condition holds. Later we investigate the properties of the principal functions corresponding to the eigenvalues and the spectral singularities.     

Order statistics from mixed exchangeable random variables

Two different exchangeable samples are considered and these two samples are assumed to be independent of each other. From these two samples a new sample is combined and treated as a single set of observations. The distribution of a single order statistic and the joint distribution of two order statistics for a new mixed sample are derived and expressed in terms of joint distribution functions. As a special case the distribution of a single order statistic and the joint distribution of two nonadjacent order statistics from exchangeable random variables are obtained. The results presented in this paper allows widespread applications in modelling of various lifetime data, biomedical sciences, reliability and survival analysis, actuarial sciences etc., where the assumption of independence of data cannot be accepted and the exchangeability is a more realistic assumption.     

Uniform convergence and computation of the generalized exponential integrals

In this paper, uniform convergence of the generalized exponential (GE) integrals is investigated. We also study the continuity, differentiability, summability and asymptotic behaviour of GE integrals. Then we give an accurate and efficient computation algorithm for these integrals.